The natural occurrence of maternal abuse of offspring in group-living monkeys is probably the closest approximation to child maltreatment provided by nonhuman animals. Infant abuse in monkeys provides the opportunity to systematically investigate the long-term developmental consequences of this adverse experience in a relatively short period of time and with invasive measurements that would be difficult to use in humans. This 5-year project has two main aims: to investigate the relative contribution of genetic and experiential variables in the intergenerational transmission of infant abuse in rhesus monkeys, and to longitudinally investigate the consequences of abusive parenting for social development, and biobehavioral reactivity to stress. Specific aims include: (1) to investigate maternal behavior and its neurobiological correlates among female monkeys that were cross-fostered at birth between abusive and nonabusive mothers; (2) to investigate the social development of 15 abused and 15 nonabused infants from birth to adulthood, (3) to investigate the behavioral reactivity to stress and the activity of stress sensitive neuroendocrine and neurochemical systems in abused and nonabused infants over a period of 5 years, including the activity of the hypothalamo-pituitary-adrenocortical (FJPA) axis and the cerebrospinal fluid concentrations of several monoamines, peptides, or their metabolites under basal conditions and following stressful challenges; (4) to investigate the neuroanatomy of several brain areas in abused and nonabused individuals at 3 and 4 years of age with structural Magnetic Resonance Imaging (MRI) studies; (5) to investigate gene expression for hormones and neurotransmitters involved in HPA axis activity and hormone receptor binding in the brain of 5 abused and 5 nonabused individuals at 5 years of age. This research will provide important new information about the mechanisms through which infant abuse is transmitted across generations in monkeys. This research will also produce a large amount of information on the behavioral, neuroendocrine, and neuroanatomical development of abused and nonabused individuals. Such information could significantly enhance our understanding of the mechanisms by which early exposure to abusive parenting or other traumatic experiences result in developmental psychopathologies. Finally, this research could also elucidate the mechanisms underlying individual differences in vulnerability or resilience to the effects of early abuse.